from Homo sacer

The Greeks had no single term to express what we mean by the word “life.” They used two terms that, although traceable to a common etymological root, are semantically and morphologically distinct: zoē, which expressed the simple fact of living common to all living beings (animals, men, or gods), and bios, which indicated the form or way of living proper to an individual or a group. When Plato mentions three kinds of life in the Philebus, and when Aristotle distinguishes the contemplative life of the philosopher (bios theōrētikos) from the life of pleasure (bios apolaustikos) and the political life (bios politikos) in the Nichomachean Ethics, neither philosopher would ever have used the term zoē (which in Greek, significantly enough, lacks a plural). This follows from the simple fact that what was at issue for both thinkers was not at all simple natural life but rather a qualified life, a particular way of life. Concerning God, Aristotle can certainly speak of a zoē aristē kai aidios, a more noble and eternal life (Metaphysics, 1072b, 28), but only insofar as he means to underline the significant truth that even God is a living being (similarly, Aristotle uses the term zoē in the same context – and in a way that is just as meaningful – to define the act of thinking). But to speak of a zoē politikē of the citizens of Athens would have made no sense.